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Abstract:

A mold used to form a midsole for an article of footwear and a method of
manufacturing are disclosed. The mold includes a first portion and a
second portion cooperating to define a midsole recess, the first portion
including a major recess and plurality of wall segments extending
throughout the major recess and cooperating to define a plurality of
minor recesses. A fillet is provided at each intersection of adjacent
wall segments. The mold may have a draft angle of less than or equal to
approximately 2.5 degrees.

Claims:

1. A method of manufacturing an article of footwear comprising injecting
a material into a midsole recess in a mold, the mold including a first
portion and a second portion cooperating to define the midsole recess,
the first portion including a major recess and plurality of wall segments
extending throughout the major recess and cooperating to define a
plurality of minor recesses, and a fillet provided at each intersection
of adjacent wall segments; closing the mold by positioning the first and
second portions in contact with one another; heating the mold for a
predetermined period of time at a predetermined temperature to form a
midsole; removing the midsole from the mold; and allowing the midsole to
expand.

2. The method of claim 1, wherein the wall segments have a draft angle of
less than or equal to approximately 2.5 degrees.

3. The method of claim 1, wherein the material is EVA.

4. The method of claim 1, wherein the first portion includes a plurality
of central recesses and a plurality of ribs, each central recess formed
in a bottom surface of a minor recess, and each rib extending upwardly
from the bottom surface around a periphery of one of the central
recesses.

5. The method of claim 1, further comprising the step of securing the
midsole to an upper.

6. The method of claim 1, further comprising the step of securing an
outsole to the midsole.

7. The method of claim 1, wherein at least one wall segment has a
thickness less than or equal to about 2.5 mm.

8. The method of claim 1, wherein a first plurality of the wall segments
extend substantially transversely across the major recess and a second
plurality of the wall segments extend substantially longitudinally along
the major recess.

9. The method of claim 1, wherein the midsole recess is substantially
foot-shaped.

10. The method of claim 1, wherein at least one fillet has a radius of
between approximately 1 mm and approximately 5 mm.

11. A mold for forming a midsole for an article of footwear comprising: a
first portion including: a major recess formed therein; a plurality of
wall segments extending throughout the recess and defining a plurality of
minor recesses within the major recess; and a plurality of fillets, each
fillet positioned between a pair of adjacent wall segments; and a second
portion, the second portion and the major recess cooperating to define a
midsole recess when the first portion and the second portion are
positioned in contact with one another such that the mold is in a closed
condition.

12. The mold of claim 11, wherein at least one wall segment has a draft
angle of less than or equal to approximately 2.5 degrees.

13. The mold of claim 11, wherein the material is EVA.

14. The mold of claim 11, wherein a first plurality of the wall segments
extend substantially transversely across the major recess and a second
plurality of the wall segments extend substantially longitudinally along
the major recess.

15. The mold of claim 11, wherein at least one wall segment has a
thickness less than or equal to about 2.5 mm.

16. The mold of claim 11, further comprising: a plurality of central
recesses, each central recess being formed in a bottom surface of one of
the minor recesses; and a plurality of ribs, each rib extending upwardly
from the bottom surface about a periphery of one of the central recesses.

17. The mold of claim 11, wherein the midsole recess is substantially
foot-shaped.

18. The mold of claim 11, wherein at least one fillet has a radius of
between approximately 1 mm and approximately 5 mm.

Description:

FIELD

[0001] Aspects of this invention relate generally to a mold for a midsole
for an article of footwear, and, in particular, to a method and mold for
manufacturing a midsole having sipes.

BACKGROUND

[0002] To keep a wearer safe and comfortable, footwear is called upon to
perform a variety of functions. For example, the sole structure of
footwear should provide adequate support and impact force attenuation
properties to prevent injury and reduce fatigue, while at the same time
provide adequate flexibility so that the sole structure articulates,
flexes, stretches, or otherwise moves to allow an individual to fully
utilize the natural motion of the foot

[0003] Conventional articles of athletic footwear generally include two
primary elements, an upper and a sole structure. The upper is secured to
the sole structure and forms a void on the interior of the footwear for
comfortably and securely receiving a foot. The sole structure is secured
to a lower portion of the upper and is positioned between the foot and
the ground. The sole structure generally incorporates multiple layers
that are conventionally referred to as an insole, a midsole, and an
outsole. The insole, or sockliner, is a thin, compressible member located
within the void and proximate a lower surface of the foot to enhance
footwear comfort. The midsole, which is conventionally secured to the
upper along the length of the upper, forms a middle layer of the sole
structure and serves a variety of purposes that include attenuating
ground (or other contact surface) reaction forces to lessen stresses upon
the foot and leg; controlling potentially harmful foot motions, such as
over pronation; and beneficially utilizing such ground reaction forces
for more efficient toe-off. The outsole forms a ground-engaging portion
(or other contact surface-engaging portion) of the sole structure, and is
formed from a durable and wear-resistant material that includes texturing
to improve traction.

[0004] The conventional midsole is primarily formed from a resilient,
polymer foam material that extends throughout the length of the footwear,
often by way of a molding process. The properties of the polymer foam
material in the midsole are primarily dependent upon factors that include
the dimensional configuration of the midsole and the specific
characteristics of the material selected for the polymer foam, including
the hardness or density of the polymer foam material. By varying these
factors throughout the midsole, the relative stiffness and degree of
ground reaction force attenuation may be altered to meet the specific
demands of the activity for which the footwear is intended to be used. In
addition to polymer foam materials, conventional midsoles may include,
for example, one or more fluid-filled bladders (e.g., filled with air or
other gasses) and moderators.

[0005] Midsoles may be formed with sipes, which are vertically extending
slots or recesses formed in the midsole that form sole elements
throughout the midsole and an articulated configuration that provides
flexibility for the footwear. The sipes may be formed during a molding
process used to form the midsole, or they may be cut into the midsole
with a hot knife or other suitable members after the midsole has been
formed.

[0006] A mold used to form a midsole may include blades extending upwardly
from a bottom portion of the mold, with the blades defining the sipes
within the material used to form the midsole. In some footwear the sipes
may be relatively narrow and relatively deep, in which case the blades
used to make such sipes may be susceptible to breakage.

[0007] It would be desirable to provide a mold and method of manufacturing
footwear with sipes that reduces or overcomes some or all of the
difficulties inherent in prior known devices. Particular advantages will
be apparent to those skilled in the art, that is, those who are
knowledgeable or experienced in this field of technology, in view of the
following disclosure of the invention and detailed description of certain
embodiments.

SUMMARY

[0008] The principles of the invention may be used to provide a mold for
footwear having sipes, and a method of manufacturing footwear having
sipes. In accordance with a first aspect, a method of manufacturing an
article of footwear includes injecting a material into a midsole recess
in a mold, the mold including a first portion and a second portion
cooperating to define the midsole recess, the first portion including a
major recess and plurality of wall segments extending throughout the
major recess and cooperating to define a plurality of minor recesses, and
a fillet provided at each intersection of adjacent wall segments; closing
the mold by positioning the first and second portions in contact with one
another; heating the mold for a predetermined period of time at a
predetermined temperature to form a midsole; removing the midsole from
the mold; and allowing the midsole to expand.

[0009] In accordance with another aspect, A mold for forming a midsole for
an article of footwear includes a first portion including a major recess
formed therein and a plurality of wall segments extending throughout the
recess and defining a plurality of minor recesses within the major
recess. Each of a plurality of fillets is positioned between a pair of
adjacent wall segments. A second portion and the major recess cooperate
to define a midsole recess when the first portion and the second portion
are positioned in contact with one another such that the mold is in a
closed condition.

[0010] By providing a mold and method of manufacturing footwear with
sipes, an article of footwear with relatively deep and narrow sipes can
be provided, which leads to improved aesthetics and performance, and
reduces the chances of the mold encountering breakage. These and
additional features and advantages disclosed here will be further
understood from the following detailed disclosure of certain embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011]FIG. 1 is an elevation view of an article of footwear with a sole
structure including sipes.

[0012]FIG. 2 is a perspective view of a bottom of the sole structure of
the article of footwear of FIG. 1.

[0013]FIG. 3 is a perspective view of a first portion of a mold use to
make the sole structure of FIG. 2.

[0014]FIG. 4 is a section view of the first portions of the mold of FIG.
3, taken along the line 4-4 in FIG. 3, shown with a second portion of the
mold in a closed condition.

[0015]FIG. 5 is a perspective view of part of the first portion of the
mold of FIG. 3.

[0016] FIG. 6 is an enlarged plan view of parts of wall segments of the
first portion of the mold of FIG. 3.

[0017]FIG. 7 is an elevation view of a wall segment of the first portion
of the mold of FIG. 3.

[0018]FIG. 8 is a section view of the mold of FIG. 3, shown with a
material used to form the midsole of the article of footwear of FIG. 1
contained within a major recess of the mold.

[0019] The figures referred to above are not drawn necessarily to scale,
should be understood to provide a representation of particular
embodiments of the invention, and are merely conceptual in nature and
illustrative of the principles involved. Some features of the mold used
to form a sole structure with sipes depicted in the drawings have been
enlarged or distorted relative to others to facilitate explanation and
understanding. The same reference numbers are used in the drawings for
similar or identical components and features shown in various alternative
embodiments. Molds used for forming footwear and sole structures for the
same as disclosed herein would have configurations and components
determined, in part, by the intended application and environment in which
they are used.

DETAILED DESCRIPTION OF CERTAIN PREFERRED EMBODIMENTS

[0020] An article of footwear 10 is depicted in FIG. 1 as including an
upper 12 and a sole structure 14. Article of footwear 10 can be any of
various articles of casual footwear having configurations suitable, for
example, for walking or lounging. Footwear 10 may also be one of a wide
range of athletic footwear styles, including shoes that are suitable for
soccer, running, basketball, baseball, cross-training, football, rugby,
tennis, and volleyball, for example. An individual skilled in the
relevant art will appreciate, therefore, that the concepts disclosed
herein with regard to footwear 10 may be applied to a wide variety of
footwear styles, in addition to the specific styles discussed herein and
depicted in the accompanying figures.

[0021] For purposes of reference in the following description, footwear 10
may be divided into three general regions: a forefoot region 16, a
midfoot region 18, and a heel region 20. Regions 16-20 are not intended
to demarcate precise areas of footwear 10. Rather, regions 16-20 are
intended to represent general areas of footwear 10 that provide a frame
of reference during the following discussion. Although regions 16-20
apply generally to footwear 10, references to regions 16-20 also may
apply specifically to upper 12, sole structure 14, or individual
components within either upper 12 or sole structure 14.

[0022] Upper 12 defines a void or chamber for receiving a foot. For
purposes of reference, upper 12 includes a medial side 22, an opposite
lateral side 24, and a vamp or instep area 26. Lateral side 24 is
positioned to extend along a lateral side of the foot (i.e., the outside)
and generally passes through each of regions 16-20. Similarly, medial
side 22 is positioned to extend along an opposite medial side of the foot
(i.e., the inside) and generally passes through each of regions 16-20.
Upper 12 may also include a closure mechanism, such as lace 28. Upper 12
also includes an ankle opening 30 that provides the foot with access to
the void within upper 12.

[0023] Sole structure 14 includes a midsole 32 positioned below upper 12.
Midsole 32 serves to provide shock-attenuation and energy-absorption for
footwear 10. In certain embodiments, midsole 32 is secured to upper 12.
Midsole 32 may be secured to upper 12 with an adhesive, for example.
Suitable adhesives are well known in the art and need not be discussed in
greater detail here. Midsole 32 may be secured to upper 12 with any other
suitable fastening means including, for example, stitching, or stitching
and adhesive. Other suitable means of fastening midsole 32 to upper 12
will become readily apparent to those skilled in the art, given the
benefit of this disclosure.

[0024] Suitable materials for midsole 32 include any of the conventional
polymer foams that are utilized in footwear midsoles, including phylon
(Ethylene Vinyl Acetate (EVA') foam), injection phylon, and polyurethane
foam. Other suitable materials for midsole 32 will become readily
apparent to those skilled in the art, given the benefit of this
disclosure.

[0025] In certain embodiments, an outsole 34 may be positioned below
midsole 32. Outsole 34 may be secured to midsole 32 and/or upper 12 with
an adhesive, or any other suitable fastening means including, for
example, stitching. In certain embodiments, outsole 34 may be formed of a
layer of material secured to and extending over a portion of the bottom
surface of midsole 32. In other embodiments, outsole 34 may be formed of
a plurality of individual outsole members 34 secured to the bottom
surface of midsole 32, as illustrated in FIG. 1. Suitable materials for
outsole 34 include any of the conventional rubber materials that are
utilized in footwear outsoles, such as carbon black rubber compound.
Other suitable materials for outsole 34 will become readily apparent to
those skilled in the art, given the benefit of this disclosure.

[0026] Midsole 32 includes a connecting portion 36 and a siped portion 38
that includes a plurality of sipes 40 defining a plurality of sole
elements 42. Connecting portion 36 has an upper surface 44 positioned
adjacent to upper 22, and may be secured directly to upper 22, thereby
providing support for the foot. Upper surface 4 may, therefore, be
contoured to conform to the natural, anatomical shape of the foot.
Accordingly, the area of upper surface 44 that is positioned in heel
region 20 may have a greater elevation than the area of upper surface 44
in forefoot region 16. In addition, upper surface 44 may form an arch
support area in midfoot region 18, and peripheral areas of upper surface
44 may be generally raised to provide a depression for receiving and
seating the foot. In further embodiments, upper surface 44 may have a
non-contoured configuration.

[0027] The thickness of connecting portion 36, which is defined as the
dimension that extends between upper surface 44 and the tops of sipes 40,
may vary along the longitudinal length of midsole 32. The thickness of
connecting portion 36 may range from approximately 5 mm to approximately
15 mm in certain embodiments. One skilled in the relevant art will
recognize, however, that a variety of thickness dimensions and variations
will be suitable for connecting portion 36.

[0028] Areas of connecting portion 36 that exhibit a relatively thin
thickness will, in general, possess more flexibility than areas of
connecting portion 36 that exhibit a greater thickness. Variations in the
thickness of connecting portion 36 may, therefore, be utilized to modify
the flexibility of sole structure 14 in specific areas. For example,
forefoot region 16 may be configured to have relatively high flexibility
by forming connecting portion 36 with a lesser thickness. A relatively
low flexibility may be imparted to midfoot region 18 by forming
connecting portion 36 with a greater thickness. Similarly, an
intermediate flexibility may be imparted to heel region 20 by forming
connecting portion 36 with a thickness that is between the thicknesses of
forefoot region 16 and midfoot region 18.

[0029] The right midsole 32 for article of footwear 10 is seen in FIG. 2.
As seen here, siped portion 38 forms a plurality of individual, separate
sole elements 42 that are separated by a plurality of sipes 40. Sole
elements 42 are discrete portions of midsole 32 that extend downward from
connecting portion 36. In addition, sole elements 42 are secured to
connecting portion 40 and may be formed of unitary, that is, one-piece
construction with connecting portion 36. The shape of each sole element
42 is determined by the positions of the various sipes 40. As depicted in
FIG. 2, some sipes 40 extend in a generally longitudinal direction along
sole structure 14, while other sipes 40 extend in a generally lateral
direction. This positioning of sipes 40 forms a majority of sole elements
42 to exhibit a generally square, rectangular, or trapezoidal shape. The
rearmost sole elements 42 have a quarter-circular shape due to the
curvature of sole structure 14 in heel region 20. It is to be appreciated
that sole elements 42 may have any desired shape.

[0030] The depth of sipes 40 and, naturally, the thickness of siped
portion 38, may vary along the longitudinal length of midsole 32. The
depth of sipes 40 may vary between approximately 5 mm and approximately
10 mm. The thickness of siped portion 38 may, in certain embodiments,
increase in a direction that extends from forefoot region 16 to heel
region 20. One skilled in the relevant art will recognize, however, that
a variety of thickness dimensions and variations will be suitable for
siped portion 36 and, therefore, for the depth of sipes 40.

[0031] The shape of each sole element 42, as discussed above, is
determined by the positions of the various sipes 40, which are incisions
or spaces that extend upward into midsole 32 and extend between sole
elements 42. Sipes 40 increase the flexibility of sole structure 14 by
forming an articulated configuration in midsole 32. Whereas the
conventional footwear midsole is a unitary element of polymer foam, sipes
40 form flexion lines in sole structure 14 and, therefore, have an effect
upon the directions of flex in midsole 32.

[0032] Lateral flexibility of sole structure 14 (i.e., flexibility in a
direction that extends between a lateral side and a medial side) is
provided by the longitudinally extending sipes 40A. The longitudinal
sipes 40A may have a straight or linear configuration, or a generally
curved or s-shaped configuration. In general, the depth of the
longitudinally extending sipes 40A increase as sipes 40 extend from
forefoot region 16 to heel region 20.

[0033] Longitudinal flexibility of sole structure 14 (i.e., flexibility in
a direction that extends between forefoot regions 16 and heel region 20)
is provided by the laterally extending sipes 40B. Sipes 40B are generally
parallel and extend in a medial-lateral direction across midsole 32.

[0034] The positions and orientations of sipes 40 are selected to
complement the natural motion of the foot during the running cycle. In
general, the motion of the foot during running proceeds as follows:
Initially, the heel strikes the ground, followed by the ball of the foot.
As the heel leaves the ground, the foot rolls forward so that the toes
make contact, and finally the entire foot leaves the ground to begin
another cycle. During the time that the foot is in contact with the
ground, the foot typically rolls from the outside or lateral side to the
inside or medial side, a process called pronation. That is, normally, the
outside of the heel strikes first and the toes on the inside of the foot
leave the ground last. Sipes 40B ensure that the foot remains in a
neutral foot-strike position and complement the neutral forward roll of
the foot as it is in contact with the ground. Sipes 40A provide lateral
flexibility in order to permit the foot to pronate naturally during the
running cycle.

[0035] A mold assembly 46 used to form midsole 32 is seen in FIGS. 3-7.
Mold assembly 46 as illustrated here is used to form the left midsole 32
of an article of footwear. It is to be appreciated that a corresponding
mold assembly can be used to from the mating right midsole for the
article of footwear. Mold assembly 46 includes a first portion 48 and a
second portion 50, which cooperate to define a midsole recess 52 in which
midsole 32 is formed. In the illustrated embodiment, first portion 48,
which is positioned beneath second portion 50, forms a bottom surface and
a portion of the medial and lateral sides of midsole 32, while second
portion 50 forms a top surface and a complimentary portion of the medial
and lateral sides of midsole 32. It is to be appreciated that in other
embodiments, first and second portions 48, 50 can have a different
positional relationship with respect to one another.

[0036] In certain embodiments, mold assembly 46 and its component parts is
formed of steel. In other embodiments, mold assembly 46 may be formed of
aluminum or other metals. Other suitable materials for mold assembly 46
will become readily apparent to those skilled in the art, given the
benefit of this disclosure.

[0037] As seen in FIG. 3, first portion 48 includes a major recess 54 that
is substantially foot-shaped and serves to defines the bottom surface and
the medial and lateral portions of midsole recess 52. A plurality of wall
segments 56 extend throughout major recess 54 and serve to define a
plurality of minor recesses 58. Wall segments 56 extend substantially
vertically upward from a bottom surface 60 of major recess 54.

[0038] A plurality of longitudinally extending wall segments 56A are
positioned in major recess 54, each of which corresponds to a
longitudinally extending sipe 40A of midsole 32. Thus, wall segments 56A
may have a straight or linear configuration, or a generally curved or
s-shaped configuration.

[0039] Similarly, a plurality of laterally extending wall segments 56B are
positioned in major recess 54, each of which corresponds to a laterally
extending sipe 40B of midsole 32. Consequently, all segments 56B are
generally parallel and extend in a medial-lateral direction across major
recess 54.

[0040] In certain embodiments, wall segments 56 are less than or equal to
approximately 2.5 mm wide, producing sipes 40 that are also less than or
equal to approximately 2.5 mm wide. As discussed below, midsole 32 will
expand upon removal from mold assembly 46, with the amount of expansion
being dependent on the material used to form midsole 32. Thus, to produce
a sipe 40 of a desired width, or height, the width or height of the
corresponding wall segment can be calculated based on the rate of
expansion of the material used to form midsole 32. It is to be
appreciated that thin and tall sipes are advantageous in that they
provide enhanced aesthetics for footwear 10 as well as improved
performance.

[0041] In certain embodiments, one or more minor recesses 58 includes a
central recess 62 formed in bottom surface 60, with a peripheral rib 64
extending upwardly from bottom surface 60 about an entire periphery of
central recess 62. Central recess 62 and peripheral rib 64 cooperate to
form a corresponding projection 66 on a bottom surface of a corresponding
sole element 42, with a peripheral groove 68 extending about an entire
periphery of projection 66. In certain embodiments, as seen in the
illustrated embodiment, projections 66 exhibit a generally square,
rectangular, or trapezoidal shape, corresponding to the sole elements 42
on which the projections 66 are positioned. It is to be appreciated that
may have any desired shape and are not necessarily limited to the shape
of the underlying sole element 42 on which they are positioned.

[0042] As seen in FIG. 6, the interior angle at the intersection of
adjacent wall segments 56A and 56B is rounded off, with a fillet 70. When
midsole 32 is formed in mold assembly 46, fillets 70 naturally cause each
sole element 42 to have rounded corners between its sidewalls. Fillets 70
provide additional material at the intersections of adjacent wall
segments 56A and 56B, thereby serving to strengthen each wall segment 56
and, therefore, reducing the possibility of fracture or other breakage of
wall segments 56. This strengthening of wall segments 56 allows the wall
segments 56 to have a greater height and to be thinner than they
otherwise without the additional strength provided by fillets 70. In
certain embodiments, fillets 70 have a radius of between approximately 1
mm and approximately 5 mm.

[0043] As noted above, wall segments 56 extend upwardly from bottom
surface 60 of major recess 54. As seen in FIG. 7, the draft angle α
is the angle between each wall segment 56 and a vertical line extending
upwardly from bottom surface 60. Typical prior art molds used for forming
footwear with sips are formed with wall segments having a draft angle of
approximately 5° or more in order to provide wall strength and
reduce the possibility of breakage.

[0044] The advantageous construction of wall segments 56 with fillets 70
allows for wall segments 56 with draft angle α that is less than or
equal to approximately 2.5°. Providing such a small draft angle
provides for sipes with straighter sides, which leads to enhanced
aesthetics as well as improved performance for footwear 10.

[0045] To form midsole 32 of the article of footwear 10 in mold assembly
46, mold assembly 46 is closed, as seen in FIG. 5, so that first portion
48 and second portion 50 are in contact with one another. It is to be
appreciated that first portion 48 and second portion 50 may be hinged
together, or they may be separate elements that are suitably aligned and
placed in contact with one another.

[0046] A material 72 is then injected into midsole recess 52 of mold
assembly 46 through one or more channels in mold assembly 46 (not shown)
in known fashion. Material 72 flows around and over wall segments 56 and
ribs 64, as well as into minor recesses 58 and central recesses 62.
Consequently, material 72 takes on the shape of midsole recess 52,
forming midsole 32. During the molding process, sipes 40 are formed in
the areas where wall segments 56 are positioned, with projections 66 and
grooves 68 being formed where recesses 62 and ribs 64 are positioned,
respectively.

[0047] In certain embodiments, material 72 is injection phylon (Ethylene
Vinyl Acetate or `EVA`). Other suitable materials for forming midsole 32
will become readily apparent to those skilled in the art, given the
benefit of this disclosure.

[0048] Mold assembly 46 with material 72 therein is then heated to a
predetermined temperature for a predetermined period of time. In certain
embodiments, mold assembly 46 is heated to a temperature of between about
125° C. and about 135° C. In certain embodiments, mold
assembly 46 is heated for between about 5 and about 8 minutes.

[0049] After this heating step is complete, mold assembly 46 is opened,
and midsole 32 is removed from mold assembly 46. It is to be appreciated
that after being removed, midsole 32 expands to some degree. The degree
to which midsole 32 expands at this point is dependent on the material of
which it is made. In certain embodiments, a midsole 32 made of injection
phylon may expand to approximately 163% of its original size. With other
materials, midsole 32 may expand to approximately 145% of its original
size. Midsole 32 is then cured and trimmed as necessary, and then secured
to upper 12 with an adhesive or other suitable fastening means. An
outsole 34 may then be secured to midsole 32 in any desired manner.

[0050] In certain embodiments, a release agent may be applied to the
surfaces of first portion 48 and second portion 50 in order to facilitate
the separation of midsole 32 from mold assembly 46 after its formation.
The release agent may be a spray release agent or any other suitable
release agent. Suitable materials for the release agent include, for
example, siloxane and water. Other suitable release agents will become
readily apparent to those skilled in the art, given the benefit of this
disclosure.

[0051] Thus, while there have been shown, described, and pointed out
fundamental novel features of various embodiments, it will be understood
that various omissions, substitutions, and changes in the form and
details of the devices illustrated, and in their operation, may be made
by those skilled in the art without departing from the spirit and scope
of the invention. For example, it is expressly intended that all
combinations of those elements and/or steps which perform substantially
the same function, in substantially the same way, to achieve the same
results are within the scope of the invention. Substitutions of elements
from one described embodiment to another are also fully intended and
contemplated. It is the intention, therefore, to be limited only as
indicated by the scope of the claims appended hereto.